This invention relates to a hinge for an opening and closing apparatus, such as a door cover, or the like, and more particularly to novel hinge plates having thereon improved means for connecting the hinge plates together. Even more particularly this invention relates to a hinge which may be releasably secured in an operational position without the use of a conventional hinge pin.
A conventional hinge mounted on an opening and closing apparatus, such as a door, generally comprises two hinge plates, each having along one edge thereof spaced projections which are curled or rolled in a fashion so as to produce thereon annular barrels or knuckles. When the barrels of the two plates are positioned in alternating, registering relation, they form, collectively, a tubular shaft. Disposed inside the tubular shaft is a hinge pin that prevents mis-alignment of the barrels, and also pivotally connects together the two hinge plates. The cost of producing such a conventional hinge is relatively high because of the necessary multi-step production process, whereby the different but complimentary hinge plates are fabricated, their tabs are folded to create the tubular barrels, and then the complimentary plates are coupled with a hinge pin. The cost of production is further increased when larger hinges are produced because thicker hinge plates must be utilized and a longer frabrication time is therefore required. Also, certain of these conventional hinges are plagued by a tendency to rise up when the door, upon being swung about its hinge axis, encounters an elevated floor surface such as carpeting.
Hinges without a tubular shaft, such as the hinge described in U.S. Pat. No. 4,658,471, also suffer from increased production costs due to multi-step production processes. A hinged card file punch as shown in U.S. Pat. No. 4,869,143 utilizes a pair of hinge plates having thereon cooperating pins and barrels, but the plates are not identical, and instead require special lug and camming surfaces to effect assembly of the punch.
It is an object of this invention, therefore, to provide a novel hinge requiring only two identical hinge plates.
It is also an object of this invention to provide a low-cost method for producing the aforesaid hinge.
Another object of this invention is to provide several optional means for releasably securing together the two plates of a hinge in an operational position, and without using a conventional hinge pin.
Other objects of the invention will be apparent hereinafter from the specification and from the recital of the appended claims, particularly when read in conjunction with the accompanying drawings.